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Ansible Handler Nginx Reload | An Intro

Are you tired of manually restarting your server every time you update your website’s content?

Ansible Handlers is the solution you need. Today, we are going to take a look at Ansible Handlers and how to set them up.

Suppose we have just updated the HTML content of our website and want to deploy it to the server. Usually, this involves copying the file over and then manually restarting the server to see the changes.

Fortunately, Ansible Handlers automates this process by letting us define actions that should be triggered when certain tasks are completed.

How to Set Up the Ansible Handler

Let’s walk through setting up an Ansible Handler to restart the Nginx server after updating website content.

name: Example Ansible playbook for Handlers
hosts: all
become: yes
remote_user: ubuntu
roles:
- handlers
# Ansible Handler: This will restart the Nginx server
handlers:
- name: Restart Nginx
service:
name: nginx
state: restarted


How to Set up the Ansible Task

Now, let’s define the tasks for installing Nginx, updating website content, and calling the Ansible handler.

• Install the Nginx Application Server:
  Here is the task to install the Nginx server:
  - name: Update apt cache and install Nginx
apt:
name: nginx
state: latest
update_cache: yes

• Update Website Content:

  Now, this playbook will copy the HTML file that we want to update to the application server.

  - name: Update apt cache and install Nginx
apt:
name: nginx
state: latest
update_cache: yes
- name: index.html copy
template: src=index.html dest=/usr/share/nginx/html/index.html

• Call the Ansible Handlers:

  Our experts would like to point out that the notify attribute is key here. Once the content is copied, a task named ‘Restart nginx’ is notified.

  This informs Ansible about the upcoming task after the content update is complete.

  - name: Update apt cache and install Nginx
apt:
name: nginx
state: latest
update_cache: yes
- name: index.html copy
template: src=index.html dest=/usr/share/nginx/html/index.html
- name: updated.html copy
template: src=updated.html dest=/usr/share/nginx/html/index.html
notify:
- Restart Nginx


How to Enforce Handler Order

By default, Ansible does not guarantee the order in which handlers are executed. However, we can enforce a specific order using the `listen` keyword.

- hosts: app_servers
tasks:
- name: Deploy the application
copy:
src: /path/to/app/
dest: /destination/on/server/
notify:
- "Clear Cache" # Execution Order 1
- "Restart App" # Execution Order 2


Here, the “Deploy the application” task notifies two handlers.

handlers:
- name: handler_clear_cache
command: /path/to/clear_cache_script.sh
listen: "Clear Cache"
- name: handler_restart_app
service:
name: my_app_service
state: restarted
listen: "Restart App"


The listen keyword makes sure that the “Clear Cache” handler runs before the “Restart App” handler, as they were listed in that order in the notify section.

Common Issues and Solutions

Sometimes, we may run into issues like Nginx not restarting via Ansible or variables not being read by handlers. Here are some quick solutions:

• Make sure the handler definition is correct, without conflicting flags like `state` and `enabled`.
• Handlers won’t read variables from tasks. In this case, we need to adjust the playbook structure or use the `validate` attribute in tasks.

At the end of the day, Ansible Handlers streamline server management tasks and makes our workflow efficient and reliable.

[Need assistance with a different issue? Our team is available 24/7.]

Conclusion

In brief, our Support Experts introduced us to Ansible Handler Nginx Reload option.